Relaxor ferroelectric substances have been used as capacitor materials because of their high permittivity as well as because of low temperature dependence and low electric-field dependence of their permittivity. Also, they have been used as piezoelectric/electrostrictive material to take full advantage of their excellent electromechanical coupling factor. Furthermore, their excellent piezoelectric characteristics have been used, for example, for ultrasonic transducers (e.g., Patent Document 1).
Patent Document 1: Japanese National Phase Laid-Open Patent Publication No. 2001-509312